There are many occasions in mammal""s life, whether for enhancing quality of life or for medical reasons, where passage of materials through a body lumen needs to be stopped. Such stoppage may be temporary, or it may be permanent or semi-permanent. Generally speaking, the body lumen may include tubes, blood vessels, cavities, canals, or any other lumens where there is an exchange or flow of media or materials, whether in the form of gases, such as air, liquids, such as water or blood or solids, such as cells. For example, an earplug is an occluder for reducing noise. It can also be used for preventing water from entering ears for swimmers. The media in the first case is air, which carries the sound wave, and in the second case is water for swimmers. In another example, an occluder for the fallopian tubes of the female mammal can prevent eggs from moving through the tube, thereby avoiding pregnancy. In a third example, there may be a need for a temporary or permanent closure of blood vessel for certain medical conditions, such as tumor control therapy. An occluder for this application is used to stop the blood flow to a targeted location either for a short period of time or permanently.
In any such occlusion application, an important factor in the proper functioning of the occluder is its size, which should be closely matched with and properly fitted in the targeted lumen of mammals. An undersized occluder will leak, allowing for passage of media which was to be blocked, while an oversized occluder may cause discomfort for the patient or lead to permanent damage to the lumen in which it is placed. Therefore, a practitioner should measure or be aware of the average size of the target lumen of the mammal and then choose an occluder having an appropriate size. Still, mismatch can occur because the targeted lumen in the mammal may not have a regularly defined shape, or the size may be outside the norm. Therefore, preferred designs would employ a material which can adapt and conform to the shape of the individual lumen.
Accordingly, there is a need in providing an occluder device which can adapt and conform to the shape of an individual mammal""s lumen. Preferably, the occluder device can be made in a one-size-fits-all design. Optionally, the occluder device can be removed and perhaps reused in appropriate circumstances.
In accordance with one embodiment of the present invention, there is provided an absorbent occluder. The absorbent occluder comprises a shape memory composition comprising a crystalline domain structure having a crystalline melting temperature (Tm) in the range of about 0xc2x0 to about 37xc2x0 C. and an absorbent material.
In accordance with another embodiment of the present invention, there is provided a method of occluding a lumen in a living mammal. The method comprises providing an occluder comprising a shape memory composition and an absorbent material, wherein the shape memory portion of the occluder has been deformed to a diameter equal to or smaller than the inner diameter of a target lumen of a living mammal, inserting the occluder into the lumen, and allowing at least the shape memory composition portion of the occluder to warm to the body temperature thereby recovering its shape and generally conforming to the diameter of the target lumen. The shape memory composition portion of the occluder comprises a crystalline domain structure having a crystalline melting temperature (Tm) in the range of about 0xc2x0 to about 37xc2x0 C.
In accordance with a further embodiment of the present invention, there is provided a method of occluding a lumen in a living mammal. The method comprises providing an occluder deformed to a diameter equal to or smaller than the inner diameter of a target lumen of a living mammal, said occluder comprising a shape memory composition having a glass transition temperature in the range of about xe2x88x92100xc2x0 to about 20xc2x0 C. and said composition comprising a crystalline domain structure having a crystalline melting temperature (Tm) in the range of about 0xc2x0 to about 37xc2x0 C., surgically inserting the occluder into the lumen, and allowing the occluder to warm to the body temperature thereby becoming elastic and conforming to the size and shape of the target lumen. In preferred embodiments, the deformed occluder is provided by a process which includes providing an occluder with a diameter equal to or larger than the inner diameter of the target lumen, warming the occluder to a temperature higher than Tm, deforming the occluder until the deformed diameter is smaller than the diameter of the target lumen, and cooling the deformed occluder to a temperature sufficiently lower than Tm to allow the composition to re-crystallize such that the occluder retains the deformed form.